As the human population grows and the effects of a changing climate can be seen across all the world’s ecosystems and societies, the need for sustainable action is strengthening at an accelerating rate. In 2015, world leaders adopted a new plan for sustainable development, establishing 17 Sustainable Development Goals to be achieved by 2030. In addition, nations, NGOs, and coalitions of stakeholders have been developing science-based strategies to tackle pressing social and environmental problems. These ambitious global goals and strategies address the great acceleration of threats to the world, aiming to reflect the urgency and scale at which change must take place. Still, to know that our goals have been met, or that our actions have led to the desired outcomes, we must monitor those systems we seek to change. We must have global data, through time, to verify that we’re on the right track – and to adapt to unanticipated consequences. This paper provides an overview of some of the biggest global environmental data gaps that currently exist – to highlight where the world may be ‘flying blind’ while trying to achieve ambitious goals for the future. While this paper is a call for action, it also provides a chance to reflect. What do these data gaps say about current conservation strategies? Do more uncertain (i.e., ‘riskier’) conservation interventions tend to be less well funded because of the gap in data? What novel insights arise from a more systematic approach to global evidence for nature and people?